rmnode

Remove node from graph

Syntax

H = rmnode(G,nodeIDs)

Description

H = rmnode(G,nodeIDs) removes the nodes specified by nodeIDs from graph G. Any edges incident upon the nodes in nodeIDs are also removed. rmnode refreshes the numbering of the nodes in H, such that if you removed node k, then nodes 1:k-1 have the same node numbers in H, and nodes k+1:numnodes(G) in G become k:numnodes(H) in H.

Examples

Remove Node from Graph

Create and plot a graph.

s = [1 1 1 2 2 3];
t = [2 3 4 3 4 4];
G = graph(s,t);
plot(G)

Remove node 1 from the graph and plot the result. The nodes in the new graph are automatically renumbered.

G = rmnode(G,1);
plot(G)

Remove Several Named Nodes from Graph

Create and plot a graph with named nodes.

s = [1 1 1 1 2 2 3 3 3 5 5];
t = [2 3 4 6 1 5 4 5 6 4 6];
names = {'New York' 'Los Angeles' 'Washington D.C.' 'Pittsburgh' ...
    'Denver' 'Austin'};
G = digraph(s,t,[],names);
plot(G)

Remove the nodes 'New York' and 'Pittsburgh' from the graph, then replot the result.

G = rmnode(G,{'New York' 'Pittsburgh'});
plot(G,'Layout','force')

Input Arguments

G — Input graph

graph object | digraph object

Input graph, specified as either a graph or digraph object. Use graph to create an undirected graph or digraph to create a directed graph.

Example: G = graph(1,2)

Example: G = digraph([1 2],[2 3])

nodeIDs — Node identifiers

node indices | node names

Node identifiers, specified as one or more node indices or node names.

This table shows the different ways to refer to one or more nodes either by their numeric node indices or by their node names.

Form	Single Node	Multiple Nodes
Node index	Scalar Example: 1	Vector Example: [1 2 3]
Node name	Character vector Example: 'A'	Cell array of character vectors Example: {'A' 'B' 'C'}
	String scalar Example: "A"	String array Example: ["A" "B" "C"]

Example: G = rmnode(G,[1 2]) removes node 1 and node 2 from graph G.

Output Arguments

H — Output graph

graph object | digraph object

Output graph, returned as a graph or digraph object.

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

Usage notes and limitations:

• The node identifiers nodeIDs must be node indices of the input graph G. Node names are not supported.

• When you construct a graph or digraph object in MATLAB^® and pass it to a MEX function generated using MATLAB Coder™, you cannot remove nodes from the graph object.

Thread-Based Environment
Run code in the background using MATLAB® backgroundPool or accelerate code with Parallel Computing Toolbox™ ThreadPool.

Version History

Introduced in R2015b